Liquid cooling apparatus

ABSTRACT

a liquid cooling apparatus provided on an apparatus having a heat unit generating heat, and configured to cool the heat unit by coolant includes; a coolant tank configured to store the coolant; a radiator configured to cool the coolant; and a coolant pipe which is a flow path of the coolant and connecting the coolant tank and the radiator. The coolant tank is arranged adjacent to the radiator in a horizontal direction when the apparatus disposed statically. A size of the coolant tank in a vertical direction is larger than a size of the coolant tank in a horizontal direction when the apparatus is disposed statically.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2005-282890, filed on Sep. 28,2005; prior Japanese Patent Application No. 2006-053568, filed on Feb.28, 2006; and prior Japanese Patent Application No. 2006-258960, filedon Sep. 25, 2006; the entire contents of which are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid cooling apparatus configuredto cool a heat unit generating heat, by coolant.

2. Description of the Related Art

A projection-type image display apparatus provided with a light sourcesuch as a lamp emitting the high brightness light and a projection lensprojecting the light emitted from the light source on a screen isgenerally known. The projection type image display apparatus has aliquid cooling apparatus for cooling the light source by a coolant, forefficiently suppressing affection caused by heat that the light sourcegenerates.

Specifically the liquid cooling apparatus has a flow path where thecoolant flows and a radiator cooling the coolant warmed. The liquidcooling apparatus also has a reserve tank (hereinafter, upper reservetank) for temporarily storing the coolant flowed into the radiator and areserve tank (hereinafter lower reserve tank) for temporarily storingthe coolant flowed out from the radiator.

The liquid cooling apparatus will be described bellow with reference toFIG. 1. As shown in FIG. 1, the liquid cooling apparatus has pipe 23connecting an object to be cooled 25 such as light source and a radiator200. The object to be cooled 25 is cooled by circulating coolant throughthe pipe 23. As a pump 24 pump out the coolant into the pipe 23, thecoolant circulates between the object to be cooled 25 and the radiator200.

The radiator 200 has inner radiator pipes 202 where the coolant passesthrough, and a heat radiation fin 203 cooling the coolant. The heatradiation fin 203 is cooled by the wind that blew to the heat radiationfin 203 from fan 206.

The liquid cooling apparatus has an upper reserve tank 204 fortemporarily storing the coolant flowed into the radiator and a lowerreserve tank 205 for temporarily storing the coolant flowed out from theradiator.

The upper reserve tank 204 is arranged on upper side of the radiator 200and the lower reserve tank 205 is arranged on lower side of the radiator200, assuming a vertical direction as an up-down direction when theprojection-type image display apparatus disposed statically.Accordingly, a load of the pump 24 pumping out the coolant into the pipe23 will be decreased.

Since, a size of the projection-type image display apparatus in theup-down direction is restricted, sizes of the upper reserve tank 204 andthe lower reserve tank 205 in the up-down direction are difficult to beenlarged. On the contrary, a capacity (a volume) of the upper reservetank 204 and the lower reserve tank 205 need to be enlarged for savingenough amount of the stored coolant.

Therefore, sizes of the upper reserve tank 204 and the lower reservetank 205 in a left-right direction (horizontal direction) are generallylarger than the sizes of the upper reserve tank 204 and the lowerreserve tank 205 in the up-down direction (vertical direction).

A coolant tank 201 storing the coolant is provided on upper side of theupper reserve tank 204, the coolant infused from an infusion opening. Alayer of air is provided in upper portion of the coolant tank 201 toimprove circulation characteristics of the coolant (for example,Unexamined Japanese Application No. 2002-357803).

As the projection-type image display apparatus, projection-type imagedisplay apparatuses of hanging from ceiling type and of mobile typeexist. In the projection-type image display apparatuses of hanging fromceiling type and of mobile type, since directions of the projection-typeimage display apparatuses are changeable, air may go into the pipe 23 orthe like. As the air goes into the pipe 23, a flow amount of the coolantwill be decreased. Accordingly, efficiency for cooling the object to becooled 25 is deteriorated.

Especially, in the upper reserve tank 204 described above, since thesize in the up-down direction (vertical direction) is smaller than thesize in the left-right direction (horizontal direction), the air willeasily go into the pipe 23 when the direction of the projection-typeimage display apparatus (that is, the liquid cooling apparatus) varies.

SUMMARY OF THE INVENTION

An aspect of a liquid cooling apparatus provided on an apparatus havinga heat unit generating heat, and configured to cool the heat unit bycoolant includes; a coolant tank configured to store the coolant; aradiator configured to cool the coolant; and a coolant pipe which is aflow path of the coolant and connecting the coolant tank and theradiator. The coolant tank is arranged adjacent to the radiator in ahorizontal direction when the apparatus disposed statically. A size ofthe coolant tank in a vertical direction is larger than a size of thecoolant tank in a horizontal direction when the apparatus is disposedstatically.

“Disposing the apparatus statically” is to dispose the apparatus on thehorizontal surface without leaning the apparatus.

According this aspect, since the size of the coolant tank in a verticaldirection is larger than the size of the coolant tank in a horizontaldirection, the air merely goes into the coolant pipe, if the directionof the liquid cooling apparatus varies. The volume of the coolant tankcan be sufficiently kept.

In an aspect of the liquid cooling apparatus according to abovedescribed aspect, the coolant pipe connects to a center portion of thecoolant tank in a vertical direction when the apparatus is disposedstatically.

According to this aspect, since the coolant pipe connects to a centerportion of the coolant tank in a vertical direction, the air merely goesinto the coolant pipe, if the liquid cooling apparatus is disposedupside down.

In an aspect of the liquid cooling apparatus according to abovedescribed aspect, the coolant tank has a shape expanding from the centerportion to upper side and expanding from the center portion to lowerside, assuming a vertical direction as up-down direction when theapparatus is disposed statically.

According to this aspect, since the coolant tank has the shape expandingfrom the center portion to upper side and expanding from the centerportion to lower side, the air merely goes into the coolant pipe, notonly if the liquid cooling apparatus is disposed upside down but if thedirection of the liquid cooling apparatus changes to various directions.

An aspect of the liquid cooling apparatus according to above describedaspect further includes infusion openings for infusing the coolant intothe coolant tank. The infusion openings are arranged on upper portionand lower portion of the coolant tank, assuming a vertical direction asup-down direction when the apparatus is disposed statically.

According to this aspect, since the infusion openings are arranged onupper portion and lower portion of the coolant tank, one of the infusionopenings faces toward upper side, if the liquid cooling apparatus isdisposed upside down. Accordingly, the coolant is easily infused intothe coolant tank.

In an aspect of the liquid cooling apparatus according to abovedescribed aspect, the coolant tank includes a pair of cooling tanks, andthe pair of cooling tanks are arranged on the both side of the radiator.

According to this aspect, since the pair of cooling tanks are arrangedon the both side of the radiator, the air merely goes into the radiator.

An aspect of a liquid cooling apparatus provided on an apparatus havinga heat unit generating heat, and configured to cool the heat unit bycoolant includes; a pair of coolant tanks configured to store thecoolant; a radiator configured to cool the coolant; and a coolant pipewhich is a flow path of the coolant and connecting the coolant tank andthe radiator. The pair of coolant tanks includes an upper tank arrangedon upper side of the radiator and a lower tank arranged on lower side ofthe radiator, assuming a vertical direction as up-down direction whenthe apparatus is disposed statically. One part on an upper surface ofthe upper tank expands upper than other part on the upper surface of theupper tank, and one part on a lower surface of the lower tank expandslower than other part on the lower surface of the lower tank. A shape ofthe upper tank is identical with a shape of the lower tank

According to this aspect, since the one part on the upper surface of theupper tank expands upper than the other part on the upper surface of theupper tank, the air gathers around the one part on the upper surface ofthe upper tank which expands upper than the other part on the uppersurface of the upper tank. Therefore, the air merely goes into thecoolant pipe, if the direction of the liquid cooling apparatus varies.

Since the shape of the upper tank is identical with the shape of thelower tank, the air merely goes into the coolant pipe, if the liquidcooling apparatus is disposed upside down.

In an aspect of the liquid cooling apparatus according to abovedescribed aspect, one part on a lower surface of the upper tank expandslower than other part on the lower surface of the upper tank, and onepart on an upper surface of the lower tank expands upper than other parton the upper surface of the lower tank.

According to this aspect, since the one part on an upper surface of thelower tank expands upper than the other part on the upper surface of thelower tank, the air gathers around the one part on the upper surface ofthe lower tank which expands upper than the other part on the uppersurface of the lower tank. Therefore, the air merely goes into thecoolant pipe, if the direction of the liquid cooling apparatus varies.

Since the shape of the upper tank is identical with the shape of thelower tank, the air merely goes into the coolant pipe, if the liquidcooling apparatus is disposed upside down.

In an aspect of the liquid cooling apparatus according to abovedescribed aspect, the coolant pipe respectively connects to centerportions of the upper tank and the lower tank in a vertical directionwhen the apparatus is disposed statically. The upper tank and the lowertank respectively have shape expanding from the center portion to upperside and expanding from the center portion to lower side, assuming avertical direction as up-down direction when the apparatus is disposedstatically.

According to this aspect, since the upper tank and the lower tankrespectively have the shape expanding from the center portion to upperside and expanding from the center portion to lower side, the air merelygoes into the coolant pipe, not only if the liquid cooling apparatus isdisposed upside down but if the direction of the liquid coolingapparatus changes to various directions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram showing a liquid cooling apparatusrelated to the present invention.

FIGS. 2A and 2B are explanatory diagrams showing a liquid coolingapparatus of an embodiment of the present invention. FIG. 2A shows thenormal arrangement, and FIG. 2B shows the upside down arrangement.

FIGS. 3A and 3B are explanatory diagrams showing another example of theliquid cooling apparatus of the embodiment of the present invention.FIG. 3A shows the normal arrangement, and FIG. 3B shows the upside downarrangement.

FIGS. 4A and 4B are explanatory diagrams showing still another exampleof the liquid cooling apparatus of the embodiment of the presentinvention. FIG. 4A shows the normal arrangement, and FIG. 4B shows theupside down arrangement.

FIGS. 5A and 5B are explanatory diagrams showing still another exampleof the liquid cooling apparatus of the embodiment of the presentinvention. FIG. 5A shows the normal arrangement, and FIG. 5B shows theupside down arrangement.

FIG. 6 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention.

FIG. 7 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention.

FIG. 8 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention.

FIG. 9 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention.

FIG. 10 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention.

FIGS. 11A to 11D are perspective views respectively showing examples ofthe shapes of a coolant tank 22F.

FIG. 12A is an explanatory diagram showing a 45° oblique arrangement ofthe liquid cooling apparatus shown in FIG. 10, and FIG. 12B is anexplanatory diagram showing a 90° oblique arrangement of the liquidcooling apparatus shown in FIG. 10.

FIGS. 13A to 13C are cross sectional views respectively showing examplesof the sectional shapes of the coolant tank 22F.

FIG. 14 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention.

FIG. 15 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention.

FIG. 16 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention.

FIG. 17 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention.

FIG. 18 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention.

FIG. 19A is a perspective view showing an example of the shape of acoolant tank 22J, and FIG. 19B is a perspective view showing an exampleof the shape of a coolant tank 22K.

FIG. 20 is an explanatory diagram showing an example in which the liquidcooling apparatus of the present invention is applied to aprojection-type image display apparatus.

FIG. 21 is an explanatory diagram showing an example in which the liquidcooling apparatus of the present invention is applied to aprojection-type image display apparatus.

FIG. 22 is a reference diagram showing a case where an air coolingapparatus is applied to the projection-type image display apparatus.

FIG. 23 is an explanatory diagram showing an example in which the liquidcooling apparatus of the present invention is applied to a projectiontype image display apparatus.

FIG. 24 is an explanatory diagram showing an example in which the liquidcooling apparatus of the present invention is applied to a projectiontype image display apparatus.

FIG. 25 is an explanatory diagram showing an example of an attachmentstructure of a projection type image display apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a liquid cooling apparatus of an embodiment of the presentinvention will be described based on FIGS. 2 to 25. Incidentally, forconvenience of description, the same reference numerals are respectivelygiven to the same constituents as the constituents of the liquid coolingapparatus of the conventional example shown in FIG. 1, and thedescription thereof is be omitted in some cases.

A vertical direction when the apparatus provided with the liquid coolingapparatus is disposed statically will be described as an up-downdirection, and a horizontal direction when the apparatus provided withthe liquid cooling apparatus is disposed statically will be described asa left-right direction. “Disposing the liquid cooling apparatus” is todispose the liquid cooling apparatus on the horizontal surface withoutleaning the liquid cooling apparatus.

FIRST EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIGS. 2A and 2B are explanatory diagrams showing an example of a liquidcooling apparatus of an embodiment of the present invention. This liquidcooling apparatus is configured to circulate the coolant between theliquid cooling jacket unit 25 and a radiator 21A. The radiator 21Aincludes an inner radiator pipe 21 a, and a radiation fin 21 b with azigzag shape around this inner radiator pipe 21 a. Moreover, at the bothof the right and left sides of this radiator 21A, coolant tanks 22A eachwith a shape such as a vertically long square cylinder or a verticallylong circular cylinder are arranged. Each of the coolant tanks 22A hassubstantially the same length (height) as the length of the side facesof the radiator 21A. Connection openings (ports) 22 a to be connected tothe inner radiator pipe 21 a are respectively formed at substantiallycentral positions in the longitudinal direction of the respectivecoolant tanks 22A. A size of the coolant tank 22A in the up-downdirection is larger than a size of the coolant tank 22A in theleft-right direction. Moreover, connection openings (ports) to beconnected to a coolant circulation pipe 23 (a coolant pipe) are alsorespectively formed at the substantially central positions in thelongitudinal direction of the respective coolant tanks 22A. That is,portions to serve as air pockets in the respective coolant tanks 22Aexist above the respective connection openings (ports). An infusionopening, where the coolant infused, is provided at each of the upper andlower ends of each of the coolant tanks 22A. The coolant circulationpipe 23 is provided with a pump 24, and by means of this pump 24 thecoolant is circulated inside the coolant circulation pipe 23 and theinner radiator pipe 21 a. The coolant cooled by the radiator 21A is ledto a liquid cooling jacket unit 25. An object to be cooled (a heat unitgenerating heat) is arranged on top of this liquid cooling jacket unit25. The coolant whose temperature increased by absorbing the heat fromthe object to be cooled is led to the radiator 21A through the coolantcirculation pipe 23. The heat transmitted to the radiation fin 21 b ofthe radiator 21A is taken away by air blown from a fan (not shown).

With the liquid cooling apparatus of the above-described configuration,the portions to serve as the air pockets in the respective coolant tanks22A will always exist above the respective connection openings (ports),either in the regular arrangement of the radiator 21A shown in FIG. 2Aor in the upside down arrangement of the radiator 21A shown in FIG. 2B.Accordingly, it is possible to use the liquid cooling apparatus in theupside down arrangement as well. Moreover, as for the whole system ofthe liquid cooling apparatus (a set including the radiator, the pump andthe like), modification such as reversing the rotation of the pump andthe like will not be needed even if the liquid cooling apparatus isarranged upside down. It should be noted that, in the case of the liquidcooling apparatus, each of the coolant tanks 22A is not limited to havesubstantially the same length (height) as the length of the side facesof the radiator 21A, and may have a shorter length (height). Moreover,the connection openings may be positioned slightly off the respectivecentral positions described above. Moreover, the coolant tank may beincorporated with the radiator or may be attached to the radiatorseparately. Moreover, the fan may also be incorporated with the radiatoror may be attached to the radiator separately. Also in the configurationexamples shown below, the situation is the same.

SECOND EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIGS. 3A and 3B are explanatory diagrams showing another example of theliquid cooling apparatus of the embodiment of the present invention.This liquid cooling apparatus differs from the liquid cooling apparatusshown in FIG. 2 in that it is provided with a radiator 21B. This liquidcooling apparatus has the configuration in common with the liquidcooling apparatus shown in FIG. 2 in every other respect. The radiator21B includes a plurality of radiator pipes 21 c arranged in parallelbetween the upper port portion and the lower port portion, and theradiation fin 21 b around the radiator pipes 21 c. Moreover, the innerradiator pipe 21 a extended from the left end face of the upper portportion of the radiator 21B is connected to the connection opening(port) 22 a positioned at the substantially central position in thelongitudinal direction of the left coolant tank 22A, and the innerradiator pipe 21 a extended from the right end face of the lower portportion of the radiator 21B is connected to the connection opening(port) 22 a positioned at the substantially central position in thelongitudinal direction of the right coolant tank 22A. With the liquidcooling apparatus of this configuration, the portions to serve as theair pockets in the respective coolant tank 22A will always exist abovethe respective connection openings (ports), either in the regulararrangement of the radiator 21B shown in FIG. 2A or in the upside downarrangement of the radiator 21B shown in FIG. 2B. Accordingly, it ispossible to use the liquid cooling apparatus in the upside downarrangement as well.

THIRD EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIGS. 4A and 4B are explanatory diagrams showing still another exampleof the liquid cooling apparatus of the embodiment of the presentinvention. The difference from the liquid cooling apparatus shown inFIG. 2 is that the inner radiator pipe 21 a is directly connected to thecoolant circulation pipe 23 without having one of the two coolant tanks22A provided. With the liquid cooling apparatus of this configuration,the portion to serve as the air pocket in the single coolant tank 22Awill always exist above the connection opening (port), either in theregular arrangement of the radiator 21A shown in FIG. 4A or in theupside down arrangement of the radiator 21A shown in FIG. 4B.Accordingly, it is possible to use the liquid cooling apparatus in theupside down arrangement as well. It should be noted that the innerradiator pipe 21 a to be directly connected to the coolant circulationpipe 23 may be formed straight and connected thereto.

FOURTH EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIGS. 5A and 5B are explanatory diagrams showing still another exampleof the liquid cooling apparatus of the embodiment of the presentinvention. The difference from the liquid cooling apparatus shown inFIG. 3 is that one of the two coolant tanks 22A is not provided. Inaddition, the inner radiator pipe 21 a extended from the left end faceof the upper port portion of the radiator 21B is directly connected tothe coolant circulation pipe 23. With the liquid cooling apparatus ofthis configuration, the portion to serve as the air pocket in thecoolant tank 22B will always exist above the connection opening (port),either in the regular arrangement of the radiator 21B shown in FIG. 5Aor in the upside down arrangement of the radiator 21B shown in FIG. 5B.Accordingly, it is possible to use the liquid cooling apparatus in theupside down arrangement as well. It should be noted that the innerradiator pipe 21 a to be directly connected to the coolant circulationpipe 23 may be formed straight and connected thereto.

FIFTH EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIG. 6 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention. Thedifference from the liquid cooling apparatus shown in FIG. 2 is that twocoolant tanks 22B are respectively provided in place of the two coolanttanks 22A. One coolant tank 22B is arranged in the shape of a hookextending from the left side to the upper side of the radiator 21A.Another coolant tank 22 is arranged in the shape of a hook extendingfrom the right side to the lower side of the radiator 21A. Moreover, theside portions as well as the upper and lower side portions of therespective coolant tanks 22B have substantially the same length (height)as the length of the side faces of the radiator 21A. The connectionopenings (ports) 22 a to be connected to the inner radiator pipe 21 aare respectively formed at the substantially central positions in thelongitudinal direction of the respective side portions. Moreover, theconnection openings (ports) to be connected to the coolant circulationpipe 23 are also respectively formed at the substantially centralpositions in the longitudinal direction of the respective side portions.Moreover, each of the coolant tanks 22B has oblique faces substantiallyperpendicular to an oblique 45° line therebetween, and has infusionopenings respectively in these oblique face portions. With the liquidcooling apparatus of this configuration, it is possible to use theliquid cooling apparatus not only in the upside down arrangement butalso in a leaned arrangement, for example, at oblique 45°. It should benoted that this configuration may include the radiator 21B or may notinclude one of the coolant tanks 22B. The infusion openings may berespectively provided at places in the vertical faces or horizontalfaces without forming the oblique faces. Moreover, the lengths of theside portions as well as the upper and lower side portions of therespective coolant tanks 22B may be shorter than the length of each sideof the radiator 21A.

SIXTH EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIG. 7 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention. Thedifference from the liquid cooling apparatus shown in FIG. 2 is that twocoolant tanks 22C are provided diagonally opposite to one another. Eachof the coolant tanks 22C has a square cylindrical shape or a circularcylindrical shape. Each of the coolant tanks 22C has the length (height)shorter than the length of the side faces of the radiator 21A. Theconnection openings (ports) 22 a to be connected to the inner radiatorpipe 21 a are respectively formed at substantially central positions inthe longitudinal direction of the respective coolant tanks 22C.Moreover, the connection openings (ports) to be connected to the coolantcirculation pipe 23 are also respectively formed at the substantiallycentral positions in the longitudinal direction of respective thecoolant tanks 22C. That is, the portions to serve as the air pockets inthe respective coolant tanks 22C always exist above the respectiveconnection openings (ports). In addition, this configuration may includethe radiator 21B or may not include one of the coolant tanks 22C.

SEVENTH EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIG. 8 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention. Thedifference from the liquid cooling apparatus shown in FIG. 2 is thatcoolant tanks 22D are respectively provided in the upper and lower sidesof the radiator 21A. Each of the coolant tanks 22D has substantially thesame length (width) as the length of the upper and lower sides of theradiator 21A, and is arranged obliquely upward to the right. At theright edge of each of the coolant tanks 22D, the highest part of thecoolant tank 22D is formed, and this part serves as the air pocket inthe regular arrangement. Moreover, at the left edge of each of thecoolant tanks 22D, the lowest part of the coolant tank 22D is formed andthis part serves as the air pocket in the upside down arrangement. Thatis, one part (right edge) on the upper surface of the coolant tank 22Dexpands upper than the other part (left edge) on the upper surface ofthe coolant tank 22D. One part (left edge) on the lower surface of thecoolant tank 22D expands lower than the other part (right edge) on thelower surface of the coolant tank 22D. The connection openings (ports)connected to the coolant circulation pipe 23 are respectively formed atthe substantially central positions in the longitudinal direction of therespective coolant tanks 22D. Moreover, in the upper coolant tank 22D,the connection opening (port) 22 a to be connected to the inner radiatorpipe 21 a is formed in the rightmost lower face, whereas in the lowercoolant tank 22D it is formed in the leftmost upper face. That is, theportions to serve as the air pockets in the respective coolant tanks 22Dalways exist above the respective connection openings (ports). It shouldbe noted that this configuration may include the radiator 21B or may notinclude one of the coolant tanks 22D.

EIGHTH EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIG. 9 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention. Thedifference from the liquid cooling apparatus shown in FIG. 8 is thatcoolant tanks 22E are respectively provided in the upper and lower sidesof the radiator 21A. Each of the coolant tanks 22E has a substantiallysquare cylindrical shape or a substantially circular cylindrical shapeor the like, the center of which protrudes upward and downward. That is,the highest part and the lowest part of each of the coolant tanks 22Eare formed at the central position of the coolant tank 22E. The highestportions respectively serve as the air pockets in the regulararrangement, whereas the lowest portions respectively serve as the airpockets in the upside down arrangement. The connection openings (ports)to be connected to the coolant circulation pipe 23 are respectivelyformed at the substantially central positions in the respective sidefaces of the respective coolant tanks 22E. Moreover, the connectionopenings (ports) 22 a to be connected to the inner radiator pipe 21 aare also formed at the substantially central positions in the respectiveside faces of the respective coolant tanks 22E. That is, the portions toserve as the air pockets in the respective coolant tanks 22E alwaysexist above the respective connection openings (ports). It should benoted that this configuration may include the radiator 21B or may notinclude one of the coolant tanks 22E.

NINTH EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIG. 10 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention. Thedifference from the liquid cooling apparatus shown in FIG. 2 is that inplace of the coolant tanks 22A each having a straight shape, coolanttanks 22F each having a shape whose central portion (the portion atwhich the connection openings are formed) is narrowed are provided. Theportions to serve as the air pockets and the portions to possibly servethe air pockets in the respective coolant tanks 22F extend to the rightand left from the corresponding connection openings, i.e., connectionopening 22 a between the inner radiator pipe 21 a and the coolant tank22F; and the connection opening between the coolant circulation pipe 23and the coolant tank 22F.

Each of the coolant tanks 22F has one of shapes shown in FIGS. 11A to11D, for example. The coolant tank 22F shown in FIG. 11A has a shapeformed by narrowing a center part of a flat square cylinder from twodirections (two faces which are not narrowed are in parallel to eachother). The coolant tank 22F shown in FIG. 11B has a shape formed bynarrowing a center part of a square cylinder from four directions. Thecoolant tank 22F shown in FIG. 11C has a flat cylindrical shape (diskshape) around the connection openings, and the connection openings existinside the edge positions of the circumferential faces of the flatcylindrical shape. The coolant tank 22F shown in FIG. 11D has a shapeformed by narrowing a central position of a vertically long circularcylindrical shape, and the connection openings are formed at thiscentral position (narrowed position).

FIGS. 12A and 12B show the states where the liquid cooling apparatusshown in FIG. 10 is leaned. As previously described, the portions toserve as the air pockets and the portions to possibly serve as the airpockets in the respective coolant tanks 22F extend to the right and leftfrom the corresponding connection openings, i.e., the connection opening22 a between the inner radiator pipe 21 a and the coolant tank 22F; andthe connection opening between the coolant circulation pipe 23 and thecoolant tank 22F. By this configuration, even if the radiator 21A isarranged not only at ±90 degrees but also obliquely at other angles,either or both of the portions to serve as the air pockets and theportions to possibly serve as the air pockets exist above the connectionopening. Accordingly, air will gather in the air pockets in whatever waythe liquid cooling apparatus is leaned, and thus air can be almostsecurely prevented from going into the piping from the connectionopenings.

The shape of the coolant tank 22F is not limited to the shapes shown inFIG. 11 and may have a sectional shape shown in FIG. 13A, a sectionalshape shown in FIG. 13B, or a sectional shape shown in FIG. 13C, forexample. That is, it suffices that the portion to serve as the airpocket and the portion to possibly serve as the air pocket in thecoolant tank 22F extend to the right and left from the connectionopenings. It should be noted that this configuration may include theradiator 21B or may not include one of the coolant tanks 22F.

TENTH EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIG. 14 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention. Thedifference from the liquid cooling apparatus shown in FIG. 6 is thatcoolant tanks 22G are provided in place of the coolant tanks 22B. Whileeach of the coolant tanks 22G has a hook shape as in the case of thecoolant tank 22B, the portion to serve as the air pocket in the sideportion of one of the coolant tanks 22G and the portion to possiblyserve as the air pocket in the side portion of another of the coolanttanks 22G extend to the right and left from the connection openings asin the case of the coolant tank 22F described above. It should be notedthat this configuration may include the radiator 21B or may not includeone of the coolant tanks 22G.

ELEVENTH EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIG. 15 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention. Thedifference from the liquid cooling apparatus shown in FIG. 7 is thatcoolant tanks 22H are provided in place of the coolant tanks 22B. Whilethe two coolant tanks 22H are arranged diagonally opposite to oneanother as in the case of the coolant tanks 22C, the portions to serveas the air pockets and the portions to possibly serve as the air pocketsof the respective coolant tanks 22H extend to the right and left fromthe connection openings as in the case of the coolant tanks 22Fdescribed above. It should be noted that this configuration may includethe radiator 21B or may not include one of the coolant tanks 22H.

TWELFTH EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIG. 16 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention. Thedifference from the liquid cooling apparatus shown in FIG. 8 is thatcoolant tanks 22I are provided in place of the coolant tanks 22D. Whilethe two coolant tanks 22I are respectively arranged in the upper andlower sides of the radiator 21A as in the case of the coolant tanks 22D,the portions to serve as the air pockets and the portions to possiblyserve as the air pockets of the respective coolant tanks 22I extend tothe right and left from the connection openings as in the case of thecoolant tanks 22F described above. It should be noted that thisconfiguration may include the radiator 21B or may not include one of thecoolant tanks 22I.

THIRTEENTH EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIG. 17 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention. Thedifference from the liquid cooling apparatus shown in FIG. 9 is thatcoolant tanks 22J are provided in place of the coolant tanks 22E. Whilethe two coolant tanks 22J are respectively arranged in the upper andlower sides of the radiator 21A as in the case of the coolant tanks 22E,the portion to serve as the air pocket and the portion to possibly serveas the air pocket of the coolant tanks 22J extend to the right and leftfrom the connection openings as in the case of the coolant tank 22Fdescribed above. Although each of the coolant tanks 22J has asubstantially beer barrel shape (circular sectional shape) as shown inFIG. 19A, it may have a square sectional shape or the like. It should benoted that this configuration may include the radiator 21B or may notinclude one of the coolant tanks 22J.

FOURTEENTH EMBODIMENT

(Configuration of Liquid Cooling Apparatus)

FIG. 18 is an explanatory diagram showing still another example of theliquid cooling apparatus of the embodiment of the present invention. Thedifference from the liquid cooling apparatus shown in FIG. 9 is thatcoolant tanks 22K are provided in place of the coolant tanks 22E. Whilethe two coolant tanks 22K are respectively arranged in the upper andlower sides of the radiator 21A as in the case of the coolant tanks 22E,the portion to serve as the air pocket and portion to possibly serve asthe air pocket of the coolant tanks 22K extend to the right and leftfrom the connection openings as in the case of the coolant tanks 22Fdescribed above. Although each of the coolant tanks 22K has asubstantially circular cylindrical shape (circular section) as shown inFIG. 19B, it may have a square cylindrical shape or the like. It shouldbe noted that this configuration may include the radiator 21B or may notinclude one of the coolant tanks 22K.

Moreover, in the liquid cooling apparatuses described above, each of thecoolant tanks includes two infusion openings respectively used for theregular arrangement and for the upside down arrangement, however, italso serves a purpose that the coolant tank is configured to includeonly one infusion opening, or that the coolant tank itself is configurednot to include a infusion opening. Moreover, the coolant tank may bepositioned not only in the surroundings of the radiator 21, but also,away from the surroundings, in front of or behind the radiator 21(positions should keep out of the way of a fan or air blown by the fan).

FIFTEENTH EMBODIMENT

(Configuration of Projection-Type Image Display Apparatus)

FIG. 20 is an explanatory diagram showing a configuration example inwhich the liquid cooling apparatus is applied to a projection-type imagedisplay apparatus of a three-plate type. This projection-type imagedisplay apparatus includes three illuminators 51R, 51G and 51B. Each ofthe illuminators 51 includes an LED (light emitting diode) 11, a taperedrod integrator 12, a polarization converter 13, and a rod integrator 15substantially shaped like a rectangular parallelepiped. The LEDs 11 arerespectively arranged on top of the liquid cooling jackets 25. Thecoolant circulation pipe 23 is connected to the liquid cooling jackets25 in series. The coolant coming out of the radiator 21A is circulatedin the following sequence: the liquid cooling jacket 25 used for the redLED 11, the liquid cooling jacket 25 used for the blue LED 11, and theliquid cooling jacket 25 used for the green LED 11. By passing lights ofthe respective colors emitted from the respective illuminators 51through liquid crystal display panels 1R, 1G and 1B used for therespective colors, image lights of the respective colors are generated.Then, the image lights of the respective colors are combined by means ofa cross dichroic prism 2 to provide a color image light. This colorimage light is projected by means of a projection lens 3.

Although, in the configuration example shown in FIG. 20, the coolantcirculation pipe 23 is linked to the three liquid cooling jackets 25 inseries, the three liquid cooling jackets 25 may be connected inparallel. Moreover, the lowest temperature coolant coming out of theradiator 21A is led to the liquid cooling jacket 25 used for the red LED11, but is not limited thereto. For example, the lowest temperaturecoolant may be supplied to an LED (Light emitting diode) or an LD (laserdiode) whose emission characteristic is likely to change withtemperature fluctuation. Moreover, the liquid cooling apparatus of thepresent invention is also applicable to a projection-type image displayapparatus of a single plate type. The liquid cooling apparatus of thepresent invention is also applicable to a projection-type image displayapparatus whose light source is a lamp. Not only the radiator 21A butalso other type of radiator or the like may be used.

FIG. 21 is an explanatory diagram showing an example of the arrangementrelationship among the optical elements and the constituents of theliquid cooling apparatus in a configuration in which the liquid coolingapparatus is applied to a projection-type image display apparatus, andthis view corresponds to the configuration shown in FIG. 20.Incidentally, FIG. 22 shows a configuration example for reference in acase where an air cooling is carried out to the projection-type imagedisplay apparatus shown in FIG. 20. Although an air cooling apparatusrequires three sets of apparatuses (three fans are needed), it ispossible to configure a single set of apparatus in the case of theliquid cooling apparatus.

SIXTEENTH EMBODIMENT

Hereinafter, a sixteenth embodiment of the present invention will bedescribed with reference to the drawing. Note that the difference fromabove described fifteenth embodiment will be described mainly.

Specifically, in the above described fifteenth embodiment, the coolantcirculation pipe is arranged so as to step over the projection lens. Onthe contrary, in the sixteenth embodiment, the coolant circulation pipeis connects each LEDs in series without stepping over the projectionlens.

(Configuration of Projection-Type Image Display Apparatus)

Hereinafter, a configuration of the projection-type image displayapparatus according to the sixteenth embodiment of the present inventionwill be described. FIG. 23 shows the projection-type image displayapparatus 100 according to the sixteenth embodiment.

As shown in FIG. 23, the projection-type image display apparatus 100includes a plurality of light sources (a red light source 125R, a greenlight source 125G, and a blue light source 125B), a plurality of taperedrod integrators (a tapered rod integrator 112R, a tapered rod integrator112G, and a tapered rod integrator 112B), a plurality of liquid crystalpanel (a liquid crystal panel 101R, a liquid crystal panel 101G, and aliquid crystal panel 101B), a dichroic prism 102, and a projection lens103.

The red light source 125R is such as an LED emitting the red light.Similarly, The green light source 125G is such as an LED emitting thegreen light and the blue light source 125B is such as an LED emittingthe blue light. The red light source 125R, the green light source 125G,and the blue light source 125B are heat units generating heat (objectsto be cooled).

The tapered rod integrator 112R unifies the red light emitted from thered light source 125R. Similarly, the tapered rod integrator 112Gunifies the green light emitted from the green light source 125G and thetapered rod integrator 112B unifies the blue light emitted from the bluelight source 125B.

The liquid crystal panel 101R modulates the red light unified by thetapered rod integrator 112R. Similarly, the liquid crystal panel 101Gmodulates the green light unified by the tapered rod integrator 112G andthe liquid crystal panel 101B modulates the blue light unified by thetapered rod integrator 112B.

The dichroic prism 102 combines the red light went out from the liquidcrystal panel 101R, the green light went out from the liquid crystalpanel 101G, and the blue light went out from the liquid crystal panel101B. The dichroic prism 102 guides the combined light toward theprojection lens 103.

The projection lens 103 projects the combined light combined by thedichroic prism 102 on a screen or the like.

Here, the projection-type image display apparatus has one of the liquidcooling apparatuses described in the first to fourteenth embodiments.Specifically, the liquid cooling apparatus has the radiator 121, thecoolant tank 122, the coolant circulation pipe 123, and a pump 124.

The radiator 121 cools the coolant warmed by the heat unit such as thered light source 125R, the green light source 125G, or the blue lightsource 125B, by means of the heat radiation fins. A fan 126 facingoutside of the projection-type image display apparatus 100 cools theheat radiation fins provided on the radiator 121. The fan 126 cools notonly the heat radiation fins but also inner of the projection-type imagedisplay apparatus 100 entirely.

The coolant tank 122 stores the coolant. As described in the first tofourteenth embodiment, various arrangements and shapes can be adopted asthe arrangement and the shape of the coolant tank 122,

The coolant circulation pipe 123 is a flow path of coolant providedaround the heat unit such as the red light source 125R, the green lightsource 125G, and the blue light source 125B. The coolant circulationpipe 123 connects to the radiator 121, the pair of coolant tanks 122,and pump 124. The coolant circulation pipe 123 connects jacket unit (notshown) where the red light source 125R, the green light source 125G, andthe blue light source 125B are arranged.

The pump 124 pumps out the coolant into the coolant circulation pipe123.

The coolant circulation pipe 123 is preferably arranged so that thecoolant cooled by the radiator 131 cools the light source having thehigh energy in sequence, when the light sources are cooled in series.The fan 126 preferably arranged around the radiator 121.

SEVENTEENTH EMBODIMENT

Hereinafter, a seventeenth embodiment of the present invention will bedescribed with reference to the drawing. Note that the difference fromabove described sixteenth embodiment will be described mainly.

Specifically, in the above described sixteenth embodiment, theprojection-type image display apparatus has the plurality of the lightsources. On the contrary, in the seventeenth embodiment, theprojection-type image display unit has single white lamp for thereplacement of the plurality of the light sources.

(Configuration of Projection-Type Image Display Apparatus)

Hereinafter, a configuration of the projection-type image displayapparatus according to the sixteenth embodiment of the present inventionwill be described. FIG. 24 shows the projection-type image displayapparatus 100 according to the sixteenth embodiment. Note that,compositions similar to the above described sixteenth embodiment (FIG.23) are designated by the similar reference numerals.

As shown in FIG. 24, the projection-type image display unit includes awhite light source 125W for the replacement of the red light source125R, the green light source 125G and the blue light source 125B.

The white light source 125W is such as an UHP lamp emitting the whitelight. The white light source is a heat unit generating heat (an objectto be cooled).

The projection-type image display unit includes a unifying means 140 forthe replacement of the tapered rod integrator 112R, the tapered rodintegrator 112G, and the tapered rod integrator 112B.

The unifying means 140 is configured of fly-eye lens, condenser lens, orthe like, and unifies the white light emitted from the white lightsource 125W. The unifying means may be includes a PBS (Polarized BeamSplitter) integrates a polarization direction of the white light emittedfrom the white light source 125W.

The projection-type image display unit includes a separating means (amirror 131 through a mirror 135). The mirror 131 through the mirror 135may be dichroic mirrors configured to reflect light having specificwavelength, and may be polarized mirrors configured to reflect lighthaving specific polarization direction.

EIGHTEENTH EMBODIMENT

Hereinafter, an eighteenth embodiment of the present invention will bedescribed with reference to the drawing. In the eighteenth embodiment,the projection-type image display apparatus hanged from the ceiling willbe described.

(Attachment Structure of Projection-Type Image Display Apparatus)

Hereinafter, the attachment structure of the projection-type imagedisplay apparatus 100 according to the eighteenth embodiment of thepresent invention will be described. FIG. 25 shows the attachmentstructure of the projection-type image display apparatus 100 accordingto the eighteenth embodiment of the present invention. Note that,compositions similar to the above described sixteenth embodiment (FIG.23) are designated by the similar reference numerals.

As shown in FIG. 25, the projection-type image display apparatus 100 isprovided with a hanging furniture 320. The hanging furniture 320 isattached to an arm unit 330 fixed to the ceiling or the like.

According to the respective embodiments, since the size of the coolanttank 122 in the up-down direction is larger than the size of the coolingtank 122 in the horizontal direction, the air merely goes into thecoolant circulation pipe 123, assuming the vertical direction as theup-down direction when the projection-type image display apparatus 100disposed statically.

Therefore, the decrease in cooling efficiency by the coolant can besuppressed, and the volume of the coolant tank 122 can be keptsufficiently.

OTHER EMBODIMENTS

Moreover, the liquid cooling apparatus of the present application is notlimited to applications to the projection-type image display apparatus,but can be applied to other apparatuses such as a personal computerincluding heat generating members (LED, CPU and the like). Particularly,the liquid cooling apparatus of the present application can be usedsuitably in devices such as: a device which is turned upside down eventemporarily at the time of assembly; a device which may be loaded upsidedown at the time of transportation; a device which may be used upsidedown in some cases (for example, an image display device of a ceilingsuspension type and the like); and an on-vehicle device (the apparatuswill also be leaned due to the inclination of the vehicle). Moreover, bycombining the plurality of above-described projection-type image displayapparatuses arranged normally (rear projection television) with theplurality of above-described projection-type image display apparatusesarranged upside down on top of the projection-type image displayapparatuses arranged normally, a large-sized image display device with amulti-screen may be realized. Alternatively, by combining the pluralityof above-described projection-type image display apparatuses arrangednormally (LCD projector) with the plurality of above-describedprojection-type image display apparatuses arranged upside down on top ofthe projection-type image display apparatuses arranged normally, an LCDprojector for displaying a high definition image may be realized.

1. A liquid cooling apparatus provided on an apparatus having a heatunit generating heat, and configured to cool the heat unit by coolantcomprising: a coolant tank configured to store the coolant; a radiatorconfigured to cool the coolant; and a coolant pipe which is a flow pathof the coolant and connecting the coolant tank and the radiator;wherein, the coolant tank is arranged adjacent to the radiator in ahorizontal direction when the apparatus disposed statically, and a sizeof the coolant tank in a vertical direction is larger than a size of thecoolant tank in a horizontal direction when the apparatus is disposedstatically.
 2. The liquid cooling apparatus according to claim 1,wherein, the coolant pipe connects to a center portion of the coolanttank in a vertical direction when the apparatus is disposed statically.3. The liquid cooling apparatus according to claim 2, wherein, thecoolant tank has a shape expanding from the center portion to upper sideand expanding from the center portion to lower side, assuming a verticaldirection as up-down direction when the apparatus is disposedstatically.
 4. The liquid cooling apparatus according to claim 2,further comprising infusion openings for infusing the coolant into thecoolant tank, wherein, the infusion openings are arranged on upperportion and lower portion of the coolant tank, assuming a verticaldirection as up-down direction when the apparatus is disposedstatically.
 5. The liquid cooling apparatus according to claim 1,wherein, the coolant tank includes a pair of cooling tanks, and the pairof cooling tanks are arranged on the both side of the radiator.
 6. Aliquid cooling apparatus provided on an apparatus having a heat unitgenerating heat, and configured to cool the heat unit by coolantcomprising: a pair of coolant tanks configured to store the coolant; aradiator configured to cool the coolant; and a coolant pipe which is aflow path of the coolant and connecting the coolant tank and theradiator; wherein, the pair of coolant tanks includes an upper tankarranged on upper side of the radiator and a lower tank arranged onlower side of the radiator, assuming a vertical direction as up-downdirection when the apparatus is disposed statically, one part on anupper surface of the upper tank expands upper than other part on theupper surface of the upper tank, one part on a lower surface of thelower tank expands lower than other part on the lower surface of thelower tank, and a shape of the upper tank is identical with a shape ofthe lower tank.
 7. The liquid cooling apparatus according to claim 6,wherein, one part on a lower surface of the upper tank expands lowerthan other part on the lower surface of the upper tank, and one part onan upper surface of the lower tank expands upper than other part on theupper surface of the lower tank.
 8. The liquid cooling apparatusaccording to claim 6, wherein, the coolant pipe respectively connects tocenter portions of the upper tank and the lower tank in a verticaldirection when the apparatus is disposed statically, and the upper tankand the lower tank respectively have shape expanding from the centerportion to upper side and expanding from the center portion to lowerside, assuming a vertical direction as up-down direction when theapparatus is disposed statically.